Regulated and Reversible Induction of Adult Human β-Cell Replication

Division of Endocrinology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania

Corresponding author: Karen K. Takane, takane{at}pitt.edu.

Abstract

Induction of proliferation in adult human β-cells is challenging. It can be accomplished by introduction of cell cycle molecules
such as cyclin-dependent kinase 6 (cdk6) and cyclin D1, but their continuous overexpression raises oncogenic concerns. We attempted to mimic normal, transient, perinatal human
β-cell proliferation by delivering these molecules in a regulated and reversible manner. Adult cadaveric islets were transduced
with doxycycline (Dox)-inducible adenoviruses expressing cdk6 or cyclin D1. End points were cdk6/cyclin D1 expression and human β-cell proliferation, survival, and function. Increasing doses of Dox led to marked dose- and time-related
increases in cdk6 and cyclin D1, accompanied by a 20-fold increase in β-cell proliferation. Notably, Dox withdrawal resulted in a reversal of both cdk6 and
cyclin D1 expression as well as β-cell proliferation. Re-exposure to Dox reinduced both cdk/cyclin expression and proliferation. β-Cell
function and survival were not adversely affected. The adenoviral tetracycline (tet)-on system has not been used previously
to drive human β-cell proliferation. Human β-cells can be induced to proliferate or arrest in a regulated, reversible manner,
temporally and quantitatively mimicking the transient perinatal physiological proliferation that occurs in human β-cells.